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  • Re: OT: Warble - was Governing the speed of a cassette desk

    From John Williamson@21:1/5 to All on Thu Jul 24 10:42:52 2025
    On 24/07/2025 10:33, NY wrote:
    "NY" <me@privacy.net> wrote in message news:105q9tm$8ha0$1@dont-email.me...
    I'm copying an audio cassette that was recorded in the 1990s - hell,
    that's 30 years ago! And I've noticed that the pitch - my Dad's voice, >>>> he's giving a talk to a society - seems to be getting fractionally
    *deeper* as time goes on during a talk that lasts about 80 minutes.

    Having solved the problem of the speed/pitch gradually slowing down as the tape recording progresses, by changing from the cassette deck in my wife's hifi to my own Technics cassette deck, I am left with another problem: warble.

    It seems to affect some tapes more than others: I've just done one tape
    with no discernable problem, but another is horrible! (The first was
    branded Sony HD-F-90; the second - the one reproduced here - is
    unbranded with no manufacturer's logo.)

    Compare <http://goosebears.co.uk/sound/Fittest%20-%20Mel.wav> and <http://goosebears.co.uk/sound/Fittest%20-%20Technics.wav>

    See my earlier comment about all analogue tape decks of that age
    needing a complete overhaul for decent quality playback.

    --
    Tciao for Now!

    John.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From NY@21:1/5 to me@privacy.net on Thu Jul 24 10:33:09 2025
    "NY" <me@privacy.net> wrote in message news:105q9tm$8ha0$1@dont-email.me...
    I'm copying an audio cassette that was recorded in the 1990s - hell,
    that's 30 years ago! And I've noticed that the pitch - my Dad's voice,
    he's giving a talk to a society - seems to be getting fractionally
    *deeper* as time goes on during a talk that lasts about 80 minutes.

    Having solved the problem of the speed/pitch gradually slowing down as the
    tape recording progresses, by changing from the cassette deck in my wife's
    hifi to my own Technics cassette deck, I am left with another problem:
    warble.

    It seems to affect some tapes more than others: I've just done one tape with
    no discernable problem, but another is horrible! (The first was branded Sony HD-F-90; the second - the one reproduced here - is unbranded with no manufacturer's logo.)

    Compare <http://goosebears.co.uk/sound/Fittest%20-%20Mel.wav> and <http://goosebears.co.uk/sound/Fittest%20-%20Technics.wav>

    There is an obvious difference in pitch which I imagine is a systematic difference, and it's very difficult to say which is the more correct.

    The "Mel" recording has spikes at about 50, 64 and 100 Hz. The "Technics" recording has them at 25, 50 and 74 Hz. Given the difference in pitch, I'm wondering whether the 25, 50 and 100 peaks are from my playback and the 64 versus 74 Hz peaks are ones from the recording - maybe the same peak played
    at different speeds. Not sure what is producing a peak at around that
    frequency - of of life's mysteries.

    This is the "Mel" recording resampled to shift the speed/pitch upwards by
    74/64 = 116% <http://goosebears.co.uk/sound/Fittest%20-%20Mel%20-%20pitch%20corrected.wav>


    But ignoring that, the first (on my wife's deck) is much cleaner than the second (on my Technics deck). What could be causing the warble - so I know
    what to clean?

    The "Mel" recording has a bit alternation of the left-right balance. That is probably the tape: the recording is from the first few seconds after the
    leader and there may be some tape damage. I'll be mixing the finished
    recording to mono because I'm pretty certain it was recorded on a mono
    recorder from a single lapel radio mike.

    --- SoupGate-Win32 v1.05
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